The present invention relates generally to laying out reference lines on a work surface and more particularly to establishing lines having predetermined angles.
In the building and remodeling trades there exists the need to efficiently establish accurate reference lines during a given project. Often it is desired that the reference lines be drawn at a predetermined angle with respect to each other. In many situations, it is desired that the lines be drawn perpendicular to one another, i.e. they establish a ninety-degree angle, on the work surface. Ninety degree angles are required for true corners, for marking parallel lines along a common base line, and for establishing walls that are perpendicular to a given supporting surface, e.g. a floor. To be efficient, tradesmen desire a tool which: allows them to quickly and accurately layout lines to a desired angle, can be used by a single person, and is readily portable so that it can be moved from one job site to another easily. In addition, the tool should not be prohibitively expensive because job site tools often need to be replaced because of theft, wear, or accidental damage.
Several economical tools exist that allow a single person to quickly lay out angular lines over a short distance, e.g. less than 3 linear feet. Examples of these tools are framing squares, speed squares, combination squares, and protractors. While these tools are efficient over short distances, a second person and additional tools are required to make layouts over longer distances. For example a long baseline layout of perpendicular lines would be accomplished as shown in FIG. 1. In FIG. 1 a series of equipment racks 104 are to be installed in parallel rows 102 inside a computer room 100 at a fixed spacings 114. In addition, the equipment racks 104 are to be perpendicular to, and spaced away from, wall 120. As can be seen in FIG. 1, a standard framing square 106 is used to establish a perpendicular line to the baseline (wall 120). After framing square 106 is in place, worker 116 holds the framing square 106 in place and then places one end of a chalk line 108 along the edge of the framing square 106 which is perpendicular to wall 120. Next, worker 110 pulls the chalk line 108 out to the desired end point and aligns the chalk string with a perpendicular edge of the framing square with assistance from worker 116. After the chalk line 108 is aligned and pulled taut, worker 110 snaps the chalk line 108 to mark a line on a floor 122. Using two workers to perform the layout shown in FIG. 1 significantly increases the cost of the job over what it would be if a single worker could perform the layout. In addition, the accuracy achieved over long baseline measurements is questionable because a lateral movement of several inches by worker 110 may not result in a perceptible error to worker 116 as they look along the long edge of the framing square 106.
Economical layout tools have been designed to address the portability shortcomings associated with standard layout tools; however, they do nothing to extend the distances over which accurate layouts can be made by a single person. Examples of improved short baseline layout tools can be found in U.S. Pat. No. 5,819,427 which discloses a pull apart carpenter""s framing square, U.S. Pat. No. 5,669,149 which discloses a folding framing square and layout tool, and U.S. Pat. No. 4,920,658 which discloses a collapsible framing square.
Thus, a need exists for an extendable layout tool that can be used by one person for establishing angular lines over longer distances. In addition, the tool should reduce in size for easy transport and the tool should not be prohibitively expensive.
An object of the present invention is to improve layout tools for establishing angular lines on a work surface. Another object of the invention is to provide a portable layout tool that is expandable for use in a variety of layout tasks. Additionally, the invention reduces in size for easy transport. Still another object of the present invention is to provide a layout tool that allows a single person to make accurate layouts over much longer distances than those possible using prior art tools and techniques, namely marking layout lines over distances longer than the open arm span of the person using the tool.
According to a first embodiment of the invention, an expandable tool for laying out and marking predetermined angular layout lines on a work surface is provided. The tool includes a first leg, second leg, and hypotenuse leg, each of which is assembled by the user such that the intersection of the first and second leg form the desired angle as determined by the hypotenuse leg.
Each leg of the tool consists of either a single leg portion (or member), or the leg can be made up of more than one leg portion. The ends of each leg are fitted with fastening mechanisms that allow the leg portion to be connected to another leg portion, or to another leg.
In an embodiment where each leg is comprised of a single portion, the tool will be realized as follows. The tool includes a first leg, a second leg and a hypotenuse leg. The first leg has a first outer edge, a first proximal end, and a first distal end, and each end has a fastening mechanism associated therewith. The second leg has a second outer edge, second proximal end, and a second distal end, and each end also has a fastening mechanism associated therewith. The hypotenuse leg has a first end and a second end, with each end having a fastening mechanism.
The first proximal end 222 of the first leg 202 couples to the second proximal end 218 of the second leg 204. The first distal end 220 of the first leg 202 couples to a first end 208 of the hypotenuse leg 206. The locations where respective legs join are referred to as intersections. The second proximal end 218 of the second leg 204 is coupled to the first proximal end 222 at one end, and the second distal end 216 is coupled to the second end 210 of the hypotenuse leg 206.
Prior to assembling the tool, the user determines the desired angle for the layout lines. For a given first leg and second leg length, the length of the hypotenuse leg will vary in order to obtain the desired angle. For example, if the desired angle is ninety degrees, the intersection of the outer edges of the first and second legs will form a ninety-degree angle. Using a marking instrument (pencil, crayon, chalk, or the like) a user can mark lines that meet at the desired angle, here ninety degrees.
According to another embodiment, one or more of the legs includes more than one leg portion, each portion of that leg will have a first fastenable end 308, 314 and 322 and a second fastenable end 310, 316 and 320, with each fastenable end having a fastening mechanism 312, 318 and 324 associated with it. For embodiments where a given leg has many leg portions, the innermost portions, i.e. portions that do not connect to another leg of the tool, will connect to additional portions of that given leg using the fastening mechanisms located at their respective first fastenable ends and second fastenable ends. In contrast, the outermost leg portions will connect to another leg using the fastening mechanism located at the proximal or distal end if the leg is a first or second leg, or at the first end or second end if it is the hypotenuse leg. When multiple first or second leg portions are used, and connected together, it is desirable that the outer edges form a straight line to aid in marking layout lines.
Other embodiments of the expandable tool will be described and others will be obvious to the reader without departing from the spirit of the disclosed invention. For example, in another embodiment one can replace the hypotenuse leg with a first and second unit which are located at the distal ends of the first and second legs, respectively. The first and second unit send out communication signals (electromagnetic, optical, sonic, etc.) such that the user is notified when the distance between the first and second unit are such that a desired angle is formed at the intersection location of the first and second legs.
The above embodiments and others will be described in detail below.